The present invention is directed generally to an auxiliary lock for the hinged cargo doors of truck trailers and more particularly to a lock device having a vertical groove in one side wall for receiving the rotatable door lock bar and furthermore having a transversely slidable lock pin insertable into a registered hole in the lock bar at a position inaccessible by a hacksaw, chain cutters or other tampering tools.
Break-ins present a significant security problem for the storage and transport of valuable cargo in large trailers associated with semi-tractor/trailer rigs. Refrigerated trailers for hauling meat are particularly susceptible to break-ins because of the value of the cargo and the ease with which the stolen cargo can be sold. The hinged rear trailer doors are equipped with a vertically extended rotatable lock bar having a handle which may be secured in a locked position against the door with a padlock. Chain cutters and other tools readily available to vandels, however, can quickly and easily destroy most conventional padlocks.
A known auxiliary trailer door lock requires a somewhat T-shaped catch bracket to be welded to the lock bar, the catch bracket having a transverse tubular extension for receiving a retractable lock pin from a housing mounted on the truck door. The lock pin is thus accessible in the gap between the housing and catch bracket for cutting the lock pin with a hacksaw or the like and thereby disabling the lock. The known lock furthermore included numerous parts, required many welds in the assembly thereof, depended upon a corrosion susceptible spring for opening and required the separate catch bracket to be welded to the pivotal door lock bar.
Accordingly, a primary object of the invention is to provide an improved lock system for a vehicle cargo door.
Another object is to provide an improved lock system which is simple and rugged in construction with a minimum number of moving parts.
Another object is to provide such a lock system which can be quickly and easily assembled.
Another object is to provide such a lock system wherein the lock pin thereof, in its locked position, is shielded by the housing thereof and thereby not directly accessible to a hacksaw, cutting torch or the like.
Another object is to provide a lock system which is independent and requires no auxiliary structure to be secured to the conventional door lock bar.
Another object is to provide such a lock system wherein the opening force on the lock pin is generated by the manual turning of a key.
Another object is to provide a vehicle cargo door lock system which is easy to install, inexpensive to manufacture and efficient in operation.